Process for casting hollow bodies



April 23, W29. H. E. FIELD PROCESS FOR CASTING HOLLOW BODIES Filed Sept.1926 al touwq Patented Apr. 23, 1929.

UNITED STATES PATENT OFFICE.

HERBERT E. FIELD, OF WHEELING, WEST VIRGINIA, ASSIGNOR TO WHEELING MOLD& FOUNDRY COMPANY, OF WHEELING, 'WEST VIRGINIA, A CORPORATION OFDELAWARE.

PROCESS FOR CASTING HOLLOW BODIES.

Application filed September 2, 1926. Serial No. 133,190.

This is an improvement in a method'and mold for castihg hollow bodies,and its main object resides in the improved method.

I have discovered that hollow bodies can be cast by utilizing as acenter eorea metal or alloy having a lower melting point than that ofthe metal' composing the hollow body, whereby the metal having a loWmelting point melts and is conducted away, leavin the hollow cast body.

llly improved process consists in casting either iron or steel aroundcertain other metals or alloys of such metals, the latter having suchheat conductivity and low melting point that when the iron or steel 01'alloy of either is poured around it, that the center low melting pointmetal conducts the heat so rapidly from the iron or steel that it willimmediately set around the center metal or alloy and form a sufficientlythick wall of iron or steel and the softer metal will afterwards alsomelt and be conducted away, leaving a clean hole that had previouslybeen occupied by the metal of high conductivity and low melting point.

In practicing my improved method I utilize a mold of suitable shape andsupport in the center of said mold metal or alloy having a lower meltingpoint than the melting point of the cast hollow body. This low meltingmetal or alloy may be composed of a solid body; or only a tubular bodywit-h a center of steel or other metal, or may consist of a hollowtubular member of metal of low melting point sufliciently heavy tooperateto cause a crust on the inner side of the metal to be cast afterwhich the tube will melt and be led away, leaving a clean center hollowcasting.

I have usually used in practice a brass center member which I find hassufiicient conductivity of heat, and is of a sufiiciently low meltingpoint that when the cast metal of higher melting point is poured aroundit, that it will act to form a crust on the surrounding cast body andwill melt and be conveyed away, forming a clean center for the castbody.

In the accompanying drawings:

Figure 1 is a vertical central sectional view of a mold for carrying outmy improved process, the metals being shown in position therein and atube that is very thin.

Figure 2 is a similar view showing the 'same is likewise true of thesump tubular metal of low melting point heavier than is shown in Figure1.

Figure 3 is a similar view showing the metal of low melting point formedin a solid bar.

Figure 4 is a vertical sectional view of my improved mold for castinghollow bodies.

In carrying out my improved method, I have a mold 1 that has a bot-tomor stool portion 2,. this stool havinga central openlng 3 thatcommunicates with a sump 4. A top portion 5 is provided, and this tophas a suitable central opening 6 made therein. The top may be composedof sand and the Passing through the top part 5 is a suitable metal bar 7composed of steel, iron or alloys thereof, which passes through theopening 6 and extends downwardly through the opening 3 formed in thestool, and preferably through the stool and slightly into the sumpportion 4. This rod 7 is made of a diameter less than the diameter ofthe opening 3 whereby there is a space around the rod. Surrounding thisrod 7 is a thin coating of brass 8 as shown in Figure 1 or a thickercoating as shown in Figure 2. The casting 9 is poured into the mold 1 inany suitable manner, for instance through the openings 10 whichcommunicate with the interior of the mold. In Figures 1 to 3 inclusiveof the drawings, all of the metals are shown in position in the mold,while in Figure 4 the metal of low melting pointhas melted and hasescaped through theopening 3 into the sump 4. The described process andthe mold may be varied somewhat so long as the variations do not departfrom the idea above described. For instance in carrying out the methodit is only essential that the metal which forms the center of thecasting shall be of a lower melting point than the metal of the casting,and as to the mold, it should be provided with some means of escape forthe metal that is melted by the pouring around it the metal forming thecasting 9.

Therefore variations may be made so long as they come within a fairinterpretation of the appended claims and without departing from thespirit and scope of the invention.

Having thus described my invention, what I claim .and desire to secureby Letters Patent of the United States is:

1. The improved method of automatically casting hollow bodies andcausing the core to flow from the mold, consisting in supportingcentrally in themold a metal core having a sufficiently lower meltingpoint than the melting point of the metal to be cast thereabout, thenpouring the metal around the core to cause it to first set and then meltand automatically flow from the mold, whereby the said core will causethe metal being cast to set to shape and then automatically melt andflow from the said mold.

2. The improved method of automatically casting hollow bodies andcausing the central core to melt and flow from the mold consisting inproviding a suitable mold and sustaining centrally within the mold ametal-core consisting of an alloy, then pouring around the alloy core ametal of sufiiciently higher temperature than the alloy core to setaround the core and then melt the said core which flows automaticallyfrom the mold.

3. The improved method of automatically casting hollow bodies andcausing the central core to melt and flow from the mold consisting inproviding a suitable mold and sustaining centrally within the mold ametal core consisting of brass,then pouring around the brass core ametal of sufiiciently higher temperature than the brass core to setaround the core and then melt the said core which flows automaticallyfrom the mold.

In testimony whereof I hereunto afiix my signature.

HERBERT IE. FIELD.

